Abstract: A control circuit for use in a magneto-optic data recording system is disclosed. The control circuitry includes proportional-integral-derivative (PID) circuitry for controlling the rotation position of a permanent magnet. Acceleration circuity is used in controlling the rotational movement of the permanent magnet. The outputs from the PID circuitry and the acceleration circuitry are selectively applied to drive circuity using a switch. The drive circuity supplies current to actuators for moving or controlling the position of the permanent magnet.

Abstract: A magneto-optic data recording system and actuating device therefor comprises a permanent magnet mounted adjacent to a magneto-optic disk medium. The permanent magnet is rotatable about its longitudinal axis to change the polarity of the magnetic field which supplied to the medium. Rotation of the magnet is achieved by activation of electromagnet actuators located laterally adjacent to the permanent magnet. Rotation of the magnet through 180.degree. is preferably achieved within less than 1 period of revolution of the disk, preferably less than 1/2 the period of revolution of the disk.

Abstract: A system for generating toric optical surfaces having two different radii (or axes) of curvature with accurate centration. A multiplicity of such surfaces for use as lenses are simultaneously created. Each surface is mounted transversely to the periphery of a spinning disk of a radius equal to one of the desired arcs. Generating, lapping and polishing tools are rotated about an axis perpendicular to the disk's axis but displaced from the disk's axis by an amount equal to the difference between the radii of the desired arcs.

Abstract: A quarterwave retarder prism such as can be used in optical recording has a shape similar to a dove prism, and has three internal reflections, with the retarder prism designed to have the emerging light beam on the same axis or collinear with the entering light beam such that the accumulated phase retardation in the device is one quarterwave over a wide range of wavelengths of light.

Abstract: An apparatus for, and a method of, reconstructing and viewing a speckled holographic image through a microscope, with the result that the speckle of the holographic image is significantly reduced, without loss of resolution of the image. A finely-structured and transparent light diffuser is interposed thru the aerial image formed by a hologram or an image formed or relayed by a lens system such as a microscope objective prior to the eyepiece. This diffuser is moved in its plane with a rotary or vibratory motion to suppress the speckle.